The progressive chlamydia testing policy: A souvenir of new science

Last summer, my roommate returned from his trip to Albania and brought us some souvenirs. Besides bringing the mandatory fridge magnet for one of the shared fridges in our living room (house tradition dictates that it must be as ugly as possible), he also brought two boxes of antibiotics that he bought there in a local supermarket. He decided to buy them ‘just in case’ because he recognized them as the drugs his GP prescribed him when he contracted chlamydia, a rather unfortunate souvenir from a seemingly fortunate night out.

A picture of the fridge magnets that my house collected over the years.

Chlamydia is a sexually transmittable infection (STI) caused by the bacterium Chlamydia trachomatis. Chlamydia is also the most common STI in the Netherlands, and, luckily for my roommate, it is easily treatable with antibiotics. So, what made my roommate bring back a stockpile of antibiotics from another country?

The Dutch and their strict antibiotics policy

In the Netherlands, antibiotics are strictly regulated and not readily available in the supermarket. So, when you encounter symptoms that could point to a chlamydia infection, or when you’re notified by someone that you might have been infected, you will first need to take a test to confirm that you are infected by chlamydia. Therefore, to my roommate, bringing the ‘over the counter’ antibiotics from abroad seemed like an efficient option to more quickly and more cheaply treat any possible future chlamydia events – or those of his roommates, as he so generously offered.

This strict policy with giving out antibiotics is something I also became a ‘victim’ of when I had a urinary tract infection about 4 years ago. I had never had one before – and I was not prepared for how much pain would be involved. Not being able to sleep from the pain led me to go to the emergency room at 3 in the morning, to only be prescribed… ibuprofen?

What I later learned (and informed my roommate of) is that there is a very good reason why the Dutch health care system is so strict with giving out antibiotics: the overuse of antibiotics drives antibiotic resistance. If more and more bacteria become drug-resistant, we could eventually end up empty-handed for the treatment of bacterial infections.

So, yes, although the ibuprofen helped me get through my 8-hour lab practical the next day, I was still in quite some discomfort for a few days. But the infection did resolve on its own, without antibiotics. Imagine having a urinary tract infection that does not resolve on its own and then being told that because we used so many antibiotics in the past, there are no drugs left to treat you anymore. That nothing can combat the bacteria, and you’ll just have to live with it. That’s exactly what we’re trying to avoid.

No symptoms – no test

We can think along the same lines with other bacterial infections – if we overprescribe antibiotics, we run the risk of the bacteria becoming resistant to everything in our medicine cabinets. This is exactly why the Netherlands recently opted for quite a progressive ‘paradigm shift’ regarding the testing and treatment policy of chlamydia infections. In the past, getting an STI test meant automatically being tested for chlamydia. However, since January 2025, the GGDs (the Dutch municipal public health services) only test for chlamydia when you show symptoms that could indicate that you are infected. This change has quite an impact, because at least 70% of women and 50% of men that are infected with chlamydia never show any symptoms.

Our previous testing and treating guidelines meant that people that tested positive for chlamydia were also advised to take antibiotics to clear the infection, even if they didn’t show any symptoms. This seems to fall out of line with the general Dutch guidelines on antibiotics – why didn’t I get antibiotics when I was in pain from my urinary tract infection, while my chlamydia symptom-free roommate could pick up his antibiotics at the public health service the next day? The reason we stuck to this ‘proactive’ detection policy for such a long time was due to the notion that chlamydia infections could have long term consequences, especially for women. In rare cases, when left untreated, chlamydia infections can travel further up into the body. This can cause inflammation and pain in the pelvis, damage to the fallopian tubes and, at later stages, infertility. To prevent this, we therefore chose to treat all chlamydia infections, even if they were asymptomatic.

Knowledge is power

So, what changed? Well, our knowledge did! A recent study investigated the consequences of chlamydia infections in a large group of Dutch women. Chlamydia infections did increase the risk of inflammation in the pelvis, but this was only the case for symptomatic infections. In addition, damage to the fallopian tubes was extremely rare, and chlamydia did not reduce the chances of getting pregnant. Another study showed that the widescale testing of women without symptoms has not led to a reduction in the number of chlamydia infections. Together, these studies indicate that there is little health benefit in the testing and treatment of asymptomatic chlamydia infections.

But should we still do it, just in case? Luckily, there is currently very little antibiotic-resistant chlamydia going around, meaning that our treatment for chlamydia is still very effective. However, the antibiotics used to treat chlamydia are sometimes also used for other bacterial infections and frequently using them can drive the antibiotic resistance of those other bacteria. For example, the antibiotic azithromycin is one of the first-line choices to treat chlamydia, but is sometimes also used in infections with the bacterium Neisseria gonorrhoeae.

Neisseria gonorrhoeae causes the STI gonorrhea, which used to be relatively rare but is becoming more and more common; in 2022, the number of reported cases rose by 48% in Europe! Alarmingly, the percentage of azithromycin-resistant gonorrhea cases in the Netherlands has also been rising over the years, which could eventually result in us having fewer treatment options in the future. The chance of developing complications, like inflammation of the pelvis, after a gonorrhea infection is higher compared to chlamydia infections. In addition, it is still unclear whether these complications are limited to the people that show symptoms, as was shown to be the case for chlamydia. So, for now, we still treat asymptomatic gonorrhea infections, and hopefully limiting our antibiotic use for chlamydia infections will help us keep the treatment of gonorrhea effective.

A future perspective

Many questions remain about this change in policy. Importantly, although research has suggested that testing of asymptomatic people does not reduce the number of chlamydia infections, we don’t know if stopping testing would increase the number of chlamydia infections. Guidelines like these are established through a complicated tug-of-war, weighing the need to battle disease in the short term against impact of our current use of antibiotics in the long-term. To me, this is a very cool example of advances in biomedical research having a direct, real-life impact on public health, illustrating that policies are fluid and can be changed as our knowledge develops.

Of course, being used to viewing chlamydia as a disease that could ‘silently’ make you infertile, this change in guidelines might feel a bit scary at first. Will regular, asymptomatic chlamydia infections now just become part of life? Accepting that as a new ‘normal’ might take some time. However, in a sense, you can relate this to how we tend to accept contracting the common cold as an unavoidable consequence of spending time in public places in the winter – perhaps we’ll eventually come to see chlamydia in a similar way. Only time will tell. Of course, if you’re really scared about encountering chlamydia, there is one centuries-old remedy that prevents you from taking home such unwanted souvenirs: the condom! It was invented by the mighty king Minos of Crete in 3000 B.C, and is probably the second-most effective way to prevent STIs – after abstinence that is… but where’s the fun in that?

Want to know more?

• 'Paradigmashift chlamydia'

  • (In Dutch) The Dutch National Public Health Institute’s own statement on the change in testing policy.

• Alexiou ZW, Hoenderboom BM, Hoebe CJPA, Dukers-Muijrers NHTM, Götz HM, van der Sande MAB, de Vries HJC, den Hartog JE, Morré SA, van Benthem BHB. Reproductive tract complication risks following Chlamydia trachomatis infections: a long-term prospective cohort study from 2008 to 2022. Lancet Reg Health Eur. 2024 Aug 17;45:101027. doi: 10.1016/j.lanepe.2024.101027. PMID: 39247903; PMCID: PMC11378087.

  • The study that directly inspired the policy change.